The invention relates to a motor vehicle seat.
A motor vehicle seat is known from WO 00/5002 A1, which has a seat frame and a backrest pivoted to the seat frame, which can be folded, when using the motor vehicle seat as a front seat in in particular two-door motor vehicles, in direction to a seating surface of the seat frame out of its essentially upright use position. The seat frame is movable for adjusting the seating longitudinal position along a rail longitudinal guide and can be locked by the means of a locking device with at least one movably mounted locking element in a previously adjusted seating longitudinal position on a locking rail, which has multiple locking positions being arranged in rail longitudinal direction one after the other, in which the locking element engages for locking the rail longitudinal guide.
The rail longitudinal guide comprises a guide rail (lower rail) to be arranged tightly to the vehicle or vehicle body as well as a guide rail (upper rail) carrying the seat frame on the side of the seat, which engage with each other such that the seat sided guide rail can be displaced along the extension direction of the rail longitudinal guide, that means in rail longitudinal direction, on the guide rail being arranged fixed to the body in order to dislocate the seat frame in rail longitudinal direction, thus to newly adjust the seating longitudinal position.
The locking rail of the rail longitudinal guide having multiple locking positions being arranged in rail longitudinal direction one after the other, wherein in said locking rail the locking element can engage for locking the rail longitudinal guide in a specific seating longitudinal position, is usually combined with the lower rail of the rail longitudinal guide to be arranged fixed to the body to a unit, in particular the locking rail can be integrated in one piece into the lower rail to be arranged fixed to the body, such that the locking positions thereof can be formed itself as lower rail hole pattern immediately in the guide rail to be arranged fixed to the body.
In order to facilitate the entry of a passenger into the rear of a motor vehicle and to provide the maximum space for the entry into the rearmost seating row, an entry aid or so called “easy-entry-function” is provided, with which the locking of the rail longitudinal guide is cancelled after folding forward the backrest in direction to the seating surface and through this the seat frame and thus the complete motor vehicle seat can be moved forward so that the maximal space for the entry into the rear or to the rearmost sitting row of the motor vehicle is guaranteed. In order to bring the motor vehicle seat subsequently again simply in its original seating longitudinal position, the original seating longitudinal position is stored as memory position by the means of a mark or memory arrangement provided therefore, so that the seat frame is automatically stopped in the memory position when moving back, wherein a stop assigned to the memory arrangement interacts with a counter stop assigned to the seat frame.
A position memory is provided for storing the memory position, wherein said position memory has an adjustment means for adjusting the memory position in rail longitudinal direction of the rail longitudinal guide and a locking element pivotably connected to the adjustment means for anchoring the memory arrangement in a specific seating longitudinal position, which engages into a separate latching rail aligned parallel to the locking rail of the seating longitudinal adjustment or into the locking rail or the lower rail hole pattern itself.
A control element is provided for controlling the engaging and disengaging of the locking element into or out of the latching or locking rail, wherein said control element guarantees that the locking element engages into the locking rail and the memory arrangement locks, when the backrest is folded forward for performing the memory function. For this the locking element is elastically preloaded in direction to an engagement with the locking rail. If the seat is in the memory position with a backrest arranged in the use position, thus essentially upright, then the control element affects the locking element such that it is lifted out of the locking rail. Additionally, it can be provided that when newly adjusting the seating longitudinal position of the motor vehicle seat with a backrest being in use position, simultaneously a new memory position is adjusted according to the newly adjusted seating longitudinal position of the motor vehicle seat.
When folding the backrest forward for exerting the easy-entry-function the control element releases on the other hand the locking element so that said element only engages with the locking rail under the action of the elastic preload and the current seating longitudinal position of the motor vehicle seat is stored as memory position. For this reason the control element is connected via a coupling mechanism, for instance via a Bowden cable to the backrest.
The control element is formed for instance as a control lever, which is preloaded elastically into a direction of a position in which said lever affects the locking element such that said locking element is lifted out of the locking rail. When folding forward the backrest against said preload the control lever is transferred in a position in which the control lever releases the locking element.
Furthermore, a locking mechanism can be assigned to the backrest, with which the backrest can be locked in its position folded forward to the seating surface so that said backrest remains permanently in the forward folded position when exerting the memory function. A release element being movable together with the seat frame and for instance mounted on the seat sided rail is assigned to this locking mechanism, wherein said releasing element is actuated when starting the memory position and is coupled to the unlocking mechanism of the backrest, for instance via a Bowden cable such that it unlocks the locking mechanism when starting the memory position. For this, a switch area, for instance in form of a ramp is provided for example on the memory arrangement, with which the release element being preferably formed as a pivotably mounted release lever interacts when approaching the memory position, wherein the release element is actuated such that it unlocks the backrest being folded forward.
The control element, which effects when folding forward the backrest the locking of the memory arrangement, as well as the release element, which effects the unlocking of the folded backrest when starting the memory position after exerting the easy-entry-function, are preferably pivotable mounted on the same bearing shaft. This bearing shaft is displaceably arranged together with the seat frame in rail longitudinal direction, that means in particular on the seat sided upper rail of the rail longitudinal direction.
Since the forces exerted, when the seat frame sided counter stop strikes the stop provided on the locking element of the memory arrangement, can be introduced via the control element directly into the very stable locking rail, the sliders, on which the control element is pivotable mounted, as well as the sliding rail provided for guiding the slider can be made cost efficiently of plastics.
The control element with which the engaging and disengaging of the locking element of the memory arrangement with the locking rail can be controlled, can furthermore serve to act, when the backrest is in use position and accordingly not locked memory arrangement, as a carrier onto the adjustment means of the memory arrangement being formed as a slider such that when adjusting the motor vehicle seat with a backrest being in the use position the memory position is automatically newly adjusted via the adjustment means according to the displacement of the motor vehicle seat. For this reason the control element engages in case of an upright backrest with the locking element of the memory arrangement and/or with the slider serving as adjustment means of the memory arrangement in a form-fitted manner.
If the memory position is once started after exerting the easy-entry-function with an upright backrest, for instance in case of a vehicle seat which can not be locked in its folded forward position, then the control element slides over a control face of the locking element of the memory arrangement, wherein said locking element is lifted out of the locking rail and engages furthermore form-fitted with the locking element or the assigned slider of the memory arrangement, so that in case of a further movement of the motor vehicle seat with a backrest being in use position the memory position can newly be adjusted. The memory position represents thus always the seating longitudinal position being started at last with the backrest being in use position.
The memory arrangement consisting of the adjustment means in form of a slider, the locking element and a control element in form of a control lever as well as optionally a comfort or release lever is realized in different manners.
In a first embodiment the memory arrangement comprises a gear rack kinematics, wherein the adjustment means in form of the slider is formed as a gear rack and the locking element is formed as a gear. The disadvantage of this embodiment are the high manufacturing costs and the tolerance tuning of the tooth contour of the gear rack kinematics for self-blocking the whole system, wherein the memory arrangement is guided in a plastic guide rail.
In an alternative embodiment the locking element is pivotably mounted vertical to the rail longitudinal direction of a latching rail, wherein the centre of rotation for mounting the locking element is arranged above the rail profile of the latching rail. The adjustment means in form of the slider is guided in a guide rail so that the arrangement of two rails, namely a latching rail and a guide rail is required, what causes considerable manufacturing costs and an increased weight as well as an impact onto the functional weight of the lower rail profile of the guide rails of the motor vehicle seat.
Due to the application of latching rails for adjusting the memory position the centre of rotation of the locking element can be arranged above the rail profile, wherein the rotation of the locking element is realized via a bearing shaft above the rail profile. Due to the centre of rotation of the locking element being arranged above the rail profile the latching behaviour of the locking element is however not optimal, when adjusting a memory position and can lead to a lifting of the locking element out of the latching position and thus to an undesired adjustment of the adjusted seating position when starting the memory position when moving back the motor vehicle seat.
It is known from the DE 100 57 721 A1 to use a carrier acting on the locking element as control element, wherein said carrier is arranged longitudinally displaceable on the seat rail and comprises a longitudinally extending base body on which, on the lower end thereof facing the locking element a carrier element provided with a carrier opening is formed. The carrier is preloaded by the means of a pressure spring, which is supported on the one hand by the seat rail and on the other hand by the carrier element, in direction to the locking element such that said carrier has the tendency to lift a latching hook of the pawl out of the latching rail, wherein simultaneously a projection of the locking element formed as a latching nose engages with the carrier opening of the carrier. The carrier is controlled by a switching means that when folding forward the backrest towards the seating surface lifts the carrier from the locking element. In order to sufficiently exact guide the carrier formed as a control pin a bore hole is required in the upper or lower rail or in the locking device with which the rail longitudinal guide is blocked.
The control element, which effects the locking of the memory arrangement when folding forward the backrest, as well as the read-out element, which effects the unlocking of the backrest being folded forward when starting the memory position after exerting the entry aid function, can be alternatively formed as pivot levers and can be pivotably mounted on the same bearing shaft. This bearing shaft is displaceably arranged together with the seat frame in rail longitudinal direction, in particular on the seat sided upper rail of the rail longitudinal guide.
Such a control element formed as a pivot lever is known from the DE 10 2005 020 696 A1. The pivot movement of the pivot lever, which is required for actuating the locking element, requires however a larger groove in the upper or seat rail, through which the stability and crash safety of the upper rail is impaired.
Since the entry aid and memory arrangement is controlled or released from the hinge fitting connecting the seat sub-frame pivotably with the backrest when folding forward the backrest towards the seating surface of the seat sub-frame, the function of the entry aid and memory arrangement depends essentially on the geometry of the hinge fitting. Since the hinge fittings of the different seat manufacturers are formed and dimensioned differently, an individual adaptation of the entry aid and memory arrangement to the respective hinge fittings has to be carried out and/or a sufficient empty run and overrun in the control chain from the hinge fitting to the locking device of the rail longitudinal adjustment and position memory of the memory arrangement has to be provided. Accordingly, it is necessary to provide different entry aid and memory arrangements for the respective hinge fittings or an expensive adaptation of the entry aid and memory arrangement to the respective hinge fitting of the different motor vehicle seats is necessary and optionally a reduced functionality of the entry aid and memory arrangement has to be accepted.